NATURAL SELECTION

Phenotype Frequency

Color
Initial Frequency
Frequency GS (Round to 2 decimal places)
0.81 White
0.25 Black
0.75 Typical
Carbon aria Allele Frequency 0.19

The Correct Answer and Explanation is:

To help clarify and calculate this Natural Selection in Insects Laboratory Simulation, let’s organize and interpret the data provided.

Given:

Total:

1000 → initial total insects
474, 513, 606, 731, 1050 → frequencies over generations (GS: Generation Survival or Generation Sample perhaps?)

Phenotypes & Frequencies:

White: 0.81
Black: 0.25
Typical: 0.75

(These frequencies don’t make sense as written because they add up to more than 1. So they must not be relative frequencies — possibly values misreported or need clarification. Let’s continue assuming those are observed counts or placeholder values.)

Carbonaria allele frequency: 0.19

Now, the question asks for:
“Frequency GS (round to 2 decimal places)”

We assume this means calculating relative frequencies of each phenotype in a specific generation, say, Generation Sample = 1000, using the data or inferred values.

If we assume “Initial Frequency” was 1000, and the frequencies 474, 513, 606, 731, 1050 represent insect counts per phenotype across generations, we can calculate relative phenotype frequencies (for GS) using this approach:

Step-by-Step Calculation:

Let’s say for one generation (e.g., Generation 1):

White: 474
Black: 250 (assumption, since 0.25 was listed)
Typical: 276 (1000 – 474 – 250)

Total: 1000

Now, calculate frequencies:

White frequency = 474 / 1000 = 0.47
Black frequency = 250 / 1000 = 0.25
Typical frequency = 276 / 1000 = 0.28

Allele Frequency (Carbonaria)

To determine the allele frequency of the carbonaria allele (black), we use the Hardy-Weinberg Principle or phenotype-based estimates.

Assume:

Carbonaria (black) is dominant
Typical is heterozygous (Bb), White is homozygous recessive (bb)
Let q = frequency of carbonaria allele = 0.19
Then p = frequency of typical allele = 1 – q = 0.81

Use:

p² = white (bb)
2pq = typical (Bb)
q² = black (BB)

Thus:

White = (p²) = (0.81)² = 0.6561
Typical = 2pq = 2(0.81)(0.19) = 0.3078
Black = q² = (0.19)² = 0.0361

Convert to decimal:

White: 0.66
Typical: 0.31
Black: 0.04

Final Answer (Frequencies GS – Rounded to 2 Decimal Places):

White: 0.66
Black: 0.04
Typical: 0.31

300-Word Explanation:

Natural selection is a core mechanism of evolution where individuals with traits better suited to their environment survive and reproduce more successfully. In this simulation, we observe how the frequencies of insect phenotypes (white, black, and typical) change across generations under environmental pressures.

The insects vary in coloration, a trait influenced by genetics. Here, “carbonaria” is the allele responsible for the dark (black) phenotype, likely advantageous in polluted environments (as seen in real-world examples like the peppered moth). In a clean environment, lighter (white) insects might have better camouflage, thus higher survival.

The frequencies of each phenotype (white, typical, and black) across generations reflect the impact of natural selection. By converting the observed counts into proportions (frequencies), we get a clearer picture of how selection operates. For example, if 474 out of 1000 insects are white, their relative frequency is 0.47. Applying genetic principles like the Hardy-Weinberg equilibrium allows us to estimate allele frequencies in the population.

Using a carbonaria allele frequency of 0.19, we calculated expected genotype and phenotype frequencies: white (homozygous recessive, bb) at 66%, typical (heterozygous, Bb) at 31%, and black (homozygous dominant, BB) at 4%. This suggests the black phenotype is rare, consistent with a lower allele frequency.

In conclusion, natural selection can be quantitatively observed by tracking changes in phenotype frequencies and connecting them to underlying allele distributions. Such simulations offer insights into evolutionary dynamics and how environmental changes can shift population genetics over time.